Aneurysms generally involve the abnormal swelling or dilation of a blood vessel such as an artery. The wall of the abnormally dilated blood vessel is typically weakened and susceptible to rupture. For example, an abdominal aortic aneurysm (AAA) is a common type of aneurysm that poses a serious health threat. A common way to treat AAA and other types of aneurysm is to place an endovascular stent graft such that the stent graft spans across and extends beyond the proximal and distal ends of the diseased portion of the vasculature. The stent graft is designed to reline the diseased vasculature, providing an alternate blood conduit that isolates the aneurysm from the high pressure flow of blood, thereby reducing or eliminating the risk of rupture.
Minimally invasive endovascular repair using stent grafts is often preferred to avoid the risks associated with traditional open surgical repair. However, these stent grafts can only be used when the graft can be placed in a stable position without covering major branch vessels. In the cases of juxtarenal aneurysm where the dilation extends up to but does not involve the renal arteries, the proximal portion of the stent graft needs to be secured to the aortic wall above the renal arteries, thereby blocking the openings to the renal arteries. Thus, patients with juxtarenal aneurysms, which represent a significant proportion of abdominal aortic aneurysm cases, are typically excluded from endovascular treatment.
To allow for endovascular repair of a wider range of cases, surgeons sometimes cut openings in the stent graft body to accommodate specific branch vessel origins, a process known as “fenestration”. Thus, for example, in treating juxtarenal aneurysms, the fenestrations or openings of the stent grafts are to be aligned with the renal arteries. Traditionally, the fenestration process involves measurements based on medical images (such as CT scans) of the vessel origins. Longitudinal distances may be measured, and relative angular locations may be estimated from a reference point.
However, these manual measurements may take a substantial amount of time and effort, particularly when multiple branch vessels must be accommodated. For example, in abdominal aortic aneurysms, fenestrations may be required for both left and right renal arteries, the superior mesenteric artery (SMA), and the celiac artery. In addition, approximations of the placement of the branch openings could lead to errors in the placement of the openings compared to the true branch vessel origins. In some cases, openings may be erroneously placed over stent struts. Therefore, there is a need for a simple yet accurate and cost-effective way to obtain fenestrated stent grafts.